Effects of sol aging on mesoporous silica thin films organization

Cetyltrimethylammionium bromide (CTAB) ternplated mesoporous silica thin films were deposited on glass slides by evaporation-induced self-assembly (EISA) process using a dip-coating method. The effects of sol aging on the mesophase structure of the thin films organization were investigated. Identification of the structures was accomplished by coupling X-ray diffiraction (XRD) and transmission electron microscope (TEM) investigations, and corresponding sol was characterized by Si-29 solution state nuclear magnetic resonance (Si-29 NMR) and UV-Vis spectrophotometer for studying the mesophase structure evolution. Results indicate that sol aging has great effects on the mesophase structure of the films organization, which includes degree of order and phase transformation of mesoporous silica thin films. To obtain a better understanding of the effects of sol aging on the mesophase structure, the theories of apparent mass fractal dimension and charge density matching were introduced to explain the self-assembly process. (C) 2007 Elsevier B.V. All rights reserved.